DescriptionThe Venusian cloud tops during nearly a full orbit of ESA’s Venus Express around the planet. The inset shows the corresponding position and relative speed of Venus Express as it approaches from its furthest distance of 66 000 km above the south pole, swooping down to 250 km above the north pole.The images were captured by the Venus Monitoring Camera on 7–8 January 2012 and are shown in false colour. The video was compiled using public data from the Venus Express data archive and was released as an ESA space science image of the week feature.

A DAY IN THE LIFE OF VENUS EXPRESS

21 January 2013

Bright and dark cloud bands wind around the poles of Venus in this beautiful sequence tracked by ESA’s Venus Express as it makes a rollercoaster orbit around the planet.

We join the spacecraft from a staggering 66 000 km above the south pole, staring down into the swirling south polar vortex. From this bird’s-eye view, half of the planet is in darkness, the ‘terminator’ marking the dividing line between the day and night sides of the planet.

Intricate features on smaller and smaller scales are revealed as Venus Express dives to just 250 km above the north pole and clouds flood the field of view, before regaining a global perspective as it climbs away from the north pole.

Goals: The European Space Agency's Venus Express was designed to study the atmosphere of Venus, from the surface to the ionosphere. The mission reused the same design as ESA's Mars Express and spare parts from other deep space missions.

Accomplishments: After arriving at Venus in April 2006, Venus Express logged many firsts. One of the most significant findings were signs that Venus had been volcanically active in the last three million years -- suggesting the planet may still be geologically active.

The orbiter also made extensive meteorological maps of Venus, providing measurements of wind fields and temperatures and the chemical composition of the atmosphere. The spacecraft found a striking double-eyed atmospheric vortex that dominates the south pole. It detected water molecules escaping into space, found concrete evidence for lightning in the Venusian atmosphere and provided infrared glimpses of the hot surface.

Venus Express, after running out of propellant, ended its mission in December 2014.

Explanation: Humanity now has a spacecraft orbiting Venus. The robotic Venus Express spacecraft launched by the European Space Agency in 2005 November arrived at Venus in 2006 April. Venus Express is now orbiting Earth's sister planet and returning pictures. Pictured above is a false-color, time-lapse movie in ultraviolet light captured by the Venus Express spacecraft as it flew over Venus' northern hemisphere in late May. Venus Express is scheduled to orbit Venus for three years and collect data that might help in answering questions that include why Venus continually generates hurricane-force winds, why Venus became so hot in the past, and if there is any current volcanic activity on Venus. It is hoped that a better understanding of Venus's hot and inhospitable climate will help humanity better understand Earth's climate as well.

On 28 November 2014, the flight control team at ESOC reported loss of contact with Venus Express.

It is possible that the remaining fuel on board VEX was exhausted during the recent periapsis-raising maneuvers and that the spacecraft is no longer in a stable attitude (the spacecraft's high-gain antenna must be kept pointed toward Earth to ensure reliable radio contact).

Repeated attempts to re-establish contact using ESA and NASA deep-space tracking stations have been made since then, and there has been some limited success in the period since 3 December.

Although a stable telemetry link is not available, some telemetry packets were successfully downlinked. These confirm that the spacecraft is oriented with its solar arrays pointing toward the Sun, and is rotating slowly.

The operations team is currently attempting to downlink the table of critical events that is stored in protected memory on board, which may give details of the sequence of events which occurred over the past few days. The root cause of the anomaly (fuel situation or otherwise) remains to be established.

We will provide an update as soon as something more concrete is known.

Today, Venus Express is in the eighth year of its fantastic mission - pretty good for a satellite originally designed for just two years of orbiting in Venus' challenging conditions.

ESA's Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.

Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24-hour orbit, travelling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.

However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.

Venus Express goes gently into the night16 December 2014 ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year. http://www.esa.int/Our_Activities/Space_Science/Venus_Express

16 December 2014

ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.

Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.

However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.

Normally, the spacecraft would perform routine thruster burns to ensure that it did not come too close to Venus and risk being lost in the atmosphere. But this unique adventure was aimed at achieving the opposite, namely reducing the altitude and allowing an exploration of previously uncharted regions of the atmosphere.

Venus Express aerobraking

The campaign also provided important experience for future missions – aerobraking can be used to enter orbit around planets with atmospheres without having to carry quite so much propellant.

Between May and June 2014, the lowest point of the orbit was gradually reduced to about 130–135 km, with the core part of the aerobraking campaign lasting from 18 June to 11 July.

After this month of ‘surfing’ in and out of the atmosphere at low altitudes, the lowest point of the orbit was raised again through a series of 15 small thruster burns, such that by 26 July it was back up to about 460 km, yielding an orbital period of just over 22 hours.

The mission then continued in a reduced science phase, as the closest approach of the spacecraft to Venus steadily decreased again naturally under gravity.

Under the assumption that there was some propellant still remaining, a decision was taken to correct this natural decay with a new series of raising manoeuvres during 23–30 November, in an attempt to prolong the mission into 2015.

However, full contact with Venus Express was lost on 28 November. Since then the telemetry and telecommand links had been partially re-established, but they were very unstable and only limited information could be retrieved.

“The available information provides evidence of the spacecraft losing attitude control most likely due to thrust problems during the raising manoeuvres,” says Patrick Martin, ESA’s Venus Express mission manager.

“It seems likely, therefore, that Venus Express exhausted its remaining propellant about half way through the planned manoeuvres last month.”

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Stonehenge no Sítio das Estrelas

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